Spatial perception and spatially-guided behavior are central to the healthy functioning of humans, and a broader knowledge of these processes will facilitate treatment and rehabilitation when they fail to develop normally or break down through disease. The studies described in this research proposal will yield data that advance our general understanding of auditory information processing, the perceptual organization of auditory space and spatially-guided behavior. Combining behavioral and neurophysiological experiments, the proposed research program exploits the acoustic imaging system of the echolocating bat, an animal that relies on the spatial analysis of dynamic auditory scenes to guide its behavior. Three inter-related lines of research are proposed: 1) perceptual studies 2) adaptive behavior studies, and 3) neural sensorimotor studies. Perceptual experiments will closely examine the analysis of auditory scenes through the integration and stream segregation of acoustic information over time. Adaptive motor experiments will utilize the bat's head-aim, pinna adjustments and vocalization patterns in target tracking tasks to study perceptually-guided behaviors that depend upon the spatial analysis of auditory scenes. Experiments on sensorimotor mechanisms will focus on the functional organization of the midbrain superior colliculus, a neural structure believed to play a role in transforming polymodal sensory information into signals relayed to brainstem structures that control appropriate orienting responses. Extracellular recording will examine the spatio-temporal patterns of neural activity that encode the direction and distance of an acoustic stimulus, and microstimulation experiments will explore how activation of local neural populations directs orientation-specific behaviors in the echolocating bat. Behavioral experiments will study the effect of superior colliculus lesions on the sensorimotor integration required for target ranging, tracking and interception by bats. Specializations and general principles arising out of the data obtained from this model system can be used to develop a broader understanding of the mechanisms that support perceptual organization and spatially-guided behavior, factors that are believed to hold importance across sensory modalities and in a variety of animal species.